ATL: IDA - Remnants - Discussion

[KBBOCA]

 https://twitter.com/wxbrad/status/1431968709971693571

[cheezyWXguy]

Radar velocities are peaking above 160mph in the ene eyewall, according to the New Orleans radar. Beam is at about 12,000 feet though, so not indicative of the surface

[Stormgodess]

 https://twitter.com/SouthernShortys/status/1431968596553572359

[Iceresistance]

AF305 SE Eyewall dropsonde, CAT 5 winds are not far from the surface . . . (Note that these are instantaneous wind speed measurements)

[Hypercane_Kyle]

SFMR 148 knots just came in seconds ago, but remember that SFMR does struggle around >130-135 knots. Shallow waters too.

Seems very suspicious -- far out from the eyewall, a bunch of missing readings and one at 168 too.

Yeah, likely garbage.

[Kazmit]

I'm gonna make a Rita comparison.

[kronotsky]

Eye, 47% RH @ 700mb.
Still dry, could get an EWRC before landfall.

Do you have a reference for relationships between upper layer eye moisture and EWRCs? Not a rhetorical question; I don't know what the mechanism would be and I am curious.

https://www.ssec.wisc.edu/~kossin/artic ... l_2012.pdf

Thank you! 47 still seems a little low judging by fig 2c

[Stormgodess]

https://twitter.com/wxbrad/status/1431968709971693571?s=20

YEh I'll be honest... been thinking they have been way too conservative with surge numbers

[GCANE]

Drop in eyewall
155knt at 900mb
120knt surface
140knt just above

[Clearcloudz]

I'm gonna make a Rita comparison.

https://i.ibb.co/CPm5jrk/Ida-4.png
https://www.weather.gov/images/lch/tropical/rita/200509211920Z-250m(RitaNearMaxIntensity).jpg

Crazy but Ida looks better in this picture.

[Blown Away]

Ida maybe a little WNW wobble and starting to feel the land, slight decline in the IR? Hopefully...

[Hypercane_Kyle]

Eyewall degrading somewhat on radar. Wouldn't be surprised if Ida maintained 130 knots all the way until landfall.

[tolakram]

saved loop

[GCANE]

The highest rain-rate convection is now onshore

[Shell Mound]

Eyewall degrading somewhat on radar. Wouldn't be surprised if Ida maintained 130 knots all the way until landfall.

Secondary banding also looks to be becoming more prominent than it was earlier. Now one can maybe speak of a formative outer eyewall.

[Hurricaneman]

Looks like the beginnings of an ERC

[underthwx]

AF305 SE Eyewall dropsonde, CAT 5 winds are not far from the surface . . . (Note that these are instantaneous wind speed measurements)

https://s9.gifyu.com/images/recon_AF305-1409A-IDA_dropsonde8_20210829-1225.png

Instantaneous wind speeds?

[Clearcloudz]

saved loop
https://i.imgur.com/EfN9eX6.gif

Man looking at this if your in New Orleans is scary, I'm seeing some northward movement recently.

[dukeblue219]

Eyewall degrading somewhat on radar. Wouldn't be surprised if Ida maintained 130 knots all the way until landfall.

There's a reason landfalling Cat 5s are so rare. Its really, really hard to keep that machine running perfectly close to land.

[drewschmaltz]

Really getting nervous about Western metropolitan areas of New Orleans, some of those high rises could see some very destructive gusts coming through. Recon showing 140kt winds VERY close to the surface.

Giving myself a math exercise here. At 155mph you'd be looking at roughly 61.5 ft/lbs of force.

https://www.britannica.com/ ...

In coastal areas, where cyclonic storms such as hurricanes and typhoons occur, maximum forces are higher, ranging upward from about 250 kilograms per square metre (50 pounds per square foot). Wind forces also increase with building height to a constant or gradient value as the effect of ground friction diminishes. The maximum design wind forces in tall buildings are about 840 kilograms per square metre (170 pounds per square foot) in typhoon areas.